WO2018003798A1

WO2018003798A1 - Method for manufacturing three-dimensionally shaped molding

Info

Publication number: WO2018003798A1
Application number: PCT/JP2017/023580
Authority: WO
Inventors: 吉田　徳雄; 暁史中村; 阿部　諭; 雅憲森本; 内野々　良幸
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2016-06-30
Filing date: 2017-06-27
Publication date: 2018-01-04
Also published as: JP6817561B2; JP2018003082A

Abstract

In order to provide a method for manufacturing a three-dimensionally shaped molding, whereby a high-precision three-dimensionally shaped molding can be obtained, an embodiment of the present invention provides a method for manufacturing a three-dimensionally shaped molding, said method comprising successively forming a plurality of solidified layers by light beam irradiation, wherein the method includes reducing pores produced by residual gas in the solidified layers.

Description

Manufacturing method of three-dimensional shaped object

The present invention relates to a method for manufacturing a three-dimensional shaped object. In more detail, this invention relates to the manufacturing method of the three-dimensional shaped molded article which forms a solidified layer by light beam irradiation to a powder layer.

A method for producing a three-dimensional shaped object by irradiating a powder material with a light beam (generally referred to as “powder bed fusion bonding method”) has been conventionally known. In this method, a three-dimensional shaped object is manufactured by alternately repeating powder layer formation and solidified layer formation based on the following steps (i) and (ii).
(I) A step of irradiating a predetermined portion of the powder layer with a light beam and sintering or melting and solidifying the powder at the predetermined portion to form a solidified layer.
(Ii) A step of forming a new powder layer on the obtained solidified layer and similarly irradiating a light beam to form a further solidified layer.

According to such a manufacturing technique, it becomes possible to manufacture a complicated three-dimensional shaped object in a short time. When an inorganic metal powder is used as the powder material, the obtained three-dimensional shaped object can be used as a mold. On the other hand, when organic resin powder is used as the powder material, the obtained three-dimensional shaped object can be used as various models.

Suppose that a metal powder is used as a powder material and a three-dimensional shaped object obtained thereby is used as a mold. As shown in FIG. 10, first, the squeezing blade 23 is moved to form a powder layer 22 having a predetermined thickness on the modeling plate 21 (see FIG. 10A). Next, the solidified layer 24 is formed from the powder layer 22 by irradiating a predetermined portion of the powder layer 22 with the light beam L (see FIG. 10B). Subsequently, a new powder layer 22 is formed on the obtained solidified layer 24, and a light beam is irradiated again to form a new solidified layer 24. When the powder layer formation and the solidified layer formation are alternately performed in this manner, the solidified layer 24 is laminated (see FIG. 10C), and finally, a three-dimensional structure composed of the laminated solidified layer 24 is formed. A shaped object can be obtained. Since the solidified layer 24 formed as the lowermost layer is coupled to the modeling plate 21, the three-dimensional modeled object and the modeling plate 21 form an integrated object, and the integrated object can be used as a mold.

JP 2010-065259 A

Here, the present inventors have found the following phenomenon in the solidified layer formation stage. Specifically, the inventors of the present application have found that when forming a solidified layer by irradiating a metal powder with a light beam, pores can locally exist in the solidified layer. When the pores are locally present in the solidified layer, the structural strength of the region where the pores are present is relatively weak due to the pores forming voids. There may be a possibility that a crack may occur as a starting point. For this reason, there is a possibility that the structural strength of the finally obtained three-dimensional shaped object is lowered due to this. That is, there is a possibility that a highly accurate three-dimensional shaped object cannot be obtained.

The present invention has been made in view of such circumstances. That is, the object of the present invention is to provide a method for manufacturing a three-dimensional shaped object that can obtain a highly accurate three-dimensional shaped object.

In order to achieve the above object, in one embodiment of the present invention,
A method for producing a three-dimensional shaped object by sequentially forming a plurality of solidified layers by irradiation with a light beam,
There is provided a method for producing a three-dimensional shaped object comprising reducing pores caused by residual gas in a solidified layer.

In one embodiment of the present invention, a highly accurate three-dimensional shaped object can be obtained.

Sectional drawing schematically showing a mode of reducing the pores in the solidified layer (FIG. 1 (a): before reducing the pores, FIG. 1 (b): after reducing the pores) Cross-sectional view schematically showing the phenomenon of pore formation Sectional drawing which showed the aspect which pinpoints the generation | occurrence | production location of a pore typically Sectional drawing schematically showing a mode in which a light beam is irradiated onto a predetermined portion of a solidified layer including pores (FIG. 4 (a): identification of occurrence of pores, FIG. 4 (b): light beam irradiation start FIG. 4 (c): after the end of light beam irradiation) FIG. 5A is a cross-sectional view schematically illustrating a mode of adjusting the light beam irradiation conditions (FIG. 5A: light beam output adjustment, FIG. 5B: light beam scanning speed adjustment, FIG. 5C: light) Beam spot diameter adjustment) Sectional drawing which showed typically the aspect which presses the predetermined part of the solidification layer containing a pore from the outside Sectional drawing which showed typically the other aspect which presses the predetermined part of the solidification layer containing a pore from the outside Sectional drawing schematically showing a mode in which a predetermined portion of the solidified layer including pores is subjected to cutting (FIG. 8A: start of cutting, FIG. 8B: after completion of cutting, FIG. c): powder filling, FIG. 8 (d): light beam irradiation) FIG. 9A is a cross-sectional view schematically showing a mode of adjusting the thickness of a layer made of powder (FIG. 9A: thickness adjustment by a squeegee blade, FIG. 9B: thickness adjustment by a powder supply nozzle, FIG. 9 (c): Thickness adjustment by powder suction nozzle) Cross-sectional views schematically showing a process aspect of stereolithography combined processing in which the powder bed fusion bonding method is performed (FIG. 10A: at the time of forming the powder layer, FIG. 10B: at the time of forming the solidified layer, FIG. c): During lamination The perspective view which showed the composition of the optical modeling compound processing machine typically Flow chart showing general operation of stereolithography combined processing machine

Hereinafter, an embodiment of the present invention will be described in more detail with reference to the drawings. The forms and dimensions of the various elements in the drawings are merely examples, and do not reflect actual forms and dimensions.

In this specification, “powder layer” means, for example, “a metal powder layer made of metal powder” or “a resin powder layer made of resin powder”. The “predetermined portion of the powder layer” substantially refers to the region of the three-dimensional shaped object to be manufactured. Therefore, by irradiating the powder existing at the predetermined location with a light beam, the powder is sintered or melted and solidified to form a three-dimensional shaped object. Further, “solidified layer” means “sintered layer or melt-solidified layer” when the powder layer is a metal powder layer, and “cured layer or melt-bonded layer” when the powder layer is a resin powder layer. "Means.

Further, the “up and down” direction described directly or indirectly in the present specification is a direction based on the positional relationship between the modeling plate and the three-dimensional shaped object, for example, and is based on the modeling plate. The side on which the shaped object is manufactured is “upward”, and the opposite side is “downward”.

[Powder bed fusion bonding method]
First, the powder bed fusion bonding method (so-called powder bed method) which is a premise of the production method of the present invention will be described. In particular, an optical modeling combined processing that additionally performs a cutting process of a three-dimensional shaped object in the powder bed fusion bonding method will be given as an example. FIG. 10 schematically shows a process aspect of stereolithographic composite processing, and FIGS. 11 and 12 are flowcharts of the main configuration and operation of the stereolithographic composite processing machine capable of performing the powder bed fusion bonding method and the cutting process. Respectively.

The stereolithography combined processing machine 1 includes a powder layer forming means 2, a light beam irradiation means 3, and a cutting means 4, as shown in FIG.

The powder layer forming means 2 is means for forming a powder layer by spreading a powder such as a metal powder or a resin powder with a predetermined thickness. The light beam irradiation means 3 is a means for irradiating a predetermined portion of the powder layer with the light beam L. The cutting means 4 is means for cutting the surface of the laminated solidified layer, that is, the surface of the three-dimensional shaped object.

The powder layer forming means 2 mainly comprises a powder table 25, a squeezing blade 23, a modeling table 20, and a modeling plate 21, as shown in FIG. The powder table 25 is a table that can be moved up and down in a powder material tank 28 whose outer periphery is surrounded by a wall 26. The squeezing blade 23 is a blade that can move in the horizontal direction to obtain the powder layer 22 by supplying the powder 19 on the powder table 25 onto the modeling table 20. The modeling table 20 is a table that can be moved up and down in a modeling tank 29 whose outer periphery is surrounded by a wall 27. The modeling plate 21 is a plate that is arranged on the modeling table 20 and serves as a base for a three-dimensional modeled object.

The light beam irradiation means 3 mainly has a light beam oscillator 30 and a galvanometer mirror 31 as shown in FIG. The light beam oscillator 30 is a device that emits a light beam L. The galvanometer mirror 31 is means for scanning the emitted light beam L into the powder layer 22, that is, scanning means for the light beam L.

The cutting means 4 mainly includes an end mill 40 and a drive mechanism 41 as shown in FIG. The end mill 40 is a cutting tool for cutting the surface of the laminated solidified layer, that is, the surface of the three-dimensional shaped object. The drive mechanism 41 is means for moving the end mill 40 to a desired location to be cut.

The operation of the stereolithography combined processing machine 1 will be described in detail. The operation of the optical modeling complex machine 1 includes a powder layer forming step (S1), a solidified layer forming step (S2), and a cutting step (S3), as shown in the flowchart of FIG. The powder layer forming step (S1) is a step for forming the powder layer 22. In the powder layer forming step (S1), first, the modeling table 20 is lowered by Δt (S11) so that the level difference between the upper surface of the modeling plate 21 and the upper end surface of the modeling tank 29 becomes Δt. Next, after raising the powder table 25 by Δt, the squeezing blade 23 is moved in the horizontal direction from the powder material tank 28 toward the modeling tank 29 as shown in FIG. Thereby, the powder 19 arranged on the powder table 25 can be transferred onto the modeling plate 21 (S12), and the powder layer 22 is formed (S13). Examples of the powder material for forming the powder layer 22 include “metal powder having an average particle diameter of about 5 μm to 100 μm” and “resin powder such as nylon, polypropylene, or ABS having an average particle diameter of about 30 μm to 100 μm”. it can. When the powder layer 22 is formed, the process proceeds to a solidified layer forming step (S2). The solidified layer forming step (S2) is a step of forming the solidified layer 24 by light beam irradiation. In the solidified layer forming step (S2), the light beam L is emitted from the light beam oscillator 30 (S21), and the light beam L is scanned to a predetermined location on the powder layer 22 by the galvano mirror 31 (S22). As a result, the powder at a predetermined location of the powder layer 22 is sintered or melted and solidified to form the solidified layer 24 as shown in FIG. 10B (S23). As the light beam L, a carbon dioxide laser, an Nd: YAG laser, a fiber laser, an ultraviolet ray, or the like may be used.

The powder layer forming step (S1) and the solidified layer forming step (S2) are alternately repeated. As a result, a plurality of solidified layers 24 are laminated as shown in FIG.

When the laminated solidified layer 24 reaches a predetermined thickness (S24), the process proceeds to the cutting step (S3). The cutting step (S3) is a step for cutting the surface of the laminated solidified layer 24, that is, the surface of the three-dimensional shaped object. A cutting step is started by driving the end mill 40 (see FIG. 10C and FIG. 11) (S31). For example, when the end mill 40 has an effective blade length of 3 mm, a cutting process of 3 mm can be performed along the height direction of the three-dimensional shaped object. When the solidified layer 24 is laminated, the end mill 40 is driven. Specifically, a cutting process is performed on the surface of the laminated solidified layer 24 while moving the end mill 40 by the drive mechanism 41 (S32). At the end of such a cutting step (S3), it is determined whether or not a desired three-dimensional shaped object has been obtained (S33). When the desired three-dimensional shaped object is not yet obtained, the process returns to the powder layer forming step (S1). Thereafter, the powder layer forming step (S1) to the cutting step (S3) are repeatedly performed to further laminate the solidified layer and perform a cutting process, whereby a desired three-dimensional shaped object is finally obtained.

[Production method of the present invention]
The present invention is characterized in the solidified layer forming stage.

Specifically, the manufacturing method of the present invention includes reducing pores 10 generated in the solidified layer 24 in the formation stage of the solidified layer 24 as shown in FIGS. 1 (a) and 1 (b). Become. More specifically, in the production method of the present invention, as shown in FIGS. 1 (a) and 1 (b), pores generated due to residual gas in the solidified layer 24 in the formation stage of the solidified layer 24. Comprising subtracting ten.

As used herein, “pore 10” refers to a void formed in the solidified layer 24 as shown in the upper right enlarged view of FIG. 1A, and is not particularly limited in cross-sectional view, but is 20 to 100 μm. Which can have the following dimensions: More specifically, the “pores 10” referred to here indicate voids generated in a high density region where the solidification density in the solidified layer 24 is, for example, 80 to 100%. In other words, the “pores 10” here refers to those that do not occur in the low / medium density region where the solidification density in the solidified layer 24 is less than 80%, for example. In the density region where the solidification density in the solidified layer is relatively low, a so-called porous region can be formed inside due to the relatively low solidification density. On the other hand, in one embodiment of the present invention, the pores 10 may exist in the density region where the solidification density is relatively high as described above. From the above, it is confirmed that the “pore 10” in the present invention is essentially different from the “porous region” formed in the density region where the solidification density in the solidified layer is relatively low. I will add to.

Although not bound by a specific theory, it is considered that the “pore 10” in the present invention can be caused by the following phenomenon. Specifically, as shown in FIG. 2, when a new solidified layer 24B is formed by irradiation with the light beam L, the irradiation heat of the light beam L is transmitted to the solidified layer 24A located in the already formed lower layer. obtain. When the irradiation heat of the light beam L is transmitted to the solidified layer 24A located in the already formed lower layer, the residual gas 5 that can locally remain in the solidified layer 24A can be expanded by the irradiation heat of the light beam L. Due to the expansion of the residual gas 5, pores 10 may be locally generated in the solidified layer 24 </ b> A located in the already formed lower layer. The “residual gas 5” here is not particularly limited. For example, the gas remaining when the light beam is applied to a predetermined portion of the powder layer remains in the solidified layer. Can occur.

As shown in FIG. 1B, when the pores 10 that can be locally generated due to the residual gas in the solidified layer 24 are reduced, the inside of the solidified layer 24 can be in a state in which voids are reduced. As used herein, “reducing pores” substantially refers to reducing the number of pores and / or the size of the pores. The term “reduce” as used herein includes those that are completely removed. When the voids are reduced, it is possible to suppress the problem that the structural strength of the region where the pores 10 are present is relatively weak due to the pores 10 forming voids. Thereby, generation | occurrence | production of the crack starting from the part (namely, area | region where the pore 10 exists) where the structural strength in a solidified layer is relatively weak can be suppressed. Thereby, the structural strength of the finally obtained three-dimensional shaped article 100 can be maintained due to the suppression of the occurrence of cracks. As a result, in one embodiment of the present invention, a highly accurate three-dimensional shaped object 100 can be obtained.

In addition, this invention may take the following aspect.

<Specific embodiment of pore>
In one embodiment, as shown in FIG. 3, the generation location of the pore 10 may be specified in advance based on the temperature difference between the pore 10 in the solidified layer 24 and the peripheral portion of the pore 10.

Specifically, as shown in FIG. 3, the uppermost surface 24a of the solidified layer 24 is irradiated with the light beam L at the formation stage of the solidified layer 24, and the light beam L is irradiated using the infrared camera 50, particularly infrared thermography. The temperature distribution in the region below the predetermined portion of the uppermost surface 24a is measured. Although not limited to a specific theory, when the pores 10 are formed in the solidified layer 24, the light beam applied to the uppermost surface 24a of the solidified layer 24 due to the pores 10 forming voids. The irradiation heat of L can be transferred into the pores 10 through the solidified layer 24. At this time, since the pore 10 forms a void, the irradiation heat of the light beam L can be caused to remain in the void due to this, that is, it can be in a “muffled” state. Therefore, when the temperature distribution in the lower region of the predetermined portion of the uppermost surface 24a irradiated with the infrared camera 50 is measured, as shown in the upper right view of FIG. The temperature distribution with the temperature region 70 at the peripheral portion of the hole 10 generation portion may be different. Specifically, as shown in the upper right view of FIG. 3, the temperature range 60 of the pore 10 generation portion can be relatively higher than the temperature range 70 of the peripheral portion of the pore 10 generation portion in plan view ( Part where the pores 10 are generated: black part in the upper right diagram in FIG. 3). By utilizing such a difference in temperature distribution, it can be specified where the pores 10 are generated.

<Mode for reducing pores generated in already formed solidified layer>
Specifically, in one embodiment of the present invention, pores in the solidified layer already formed may be reduced according to the following mode.

In one embodiment, as shown in FIG. 4, the location where the pores 10 are generated is specified, and then the predetermined portion 24 ′ of the solidified layer 24 including the pores 10 is irradiated with the light beam L so as to It may be melted to reduce the pores 10.

Specifically, as shown in FIG. 4A, the location where the pores 10 are generated is specified in advance using the infrared camera 50 described above. After specifying the location where the pores 10 are generated, a predetermined portion 24 ′ of the solidified layer 24 including the pores 10 is irradiated with the light beam L as shown in FIG. Here, the “light beam L” may be used when forming a new solidified layer (corresponding to the uppermost solidified layer in FIG. 4B). When the light beam L is irradiated, the predetermined portion 24 ′ of the solidified layer 24 including the pores 10 can be in a molten state. Thereafter, as shown in FIG. 4C, the predetermined portion 24 ′ of the solidified layer 24 including the pores 10 in a molten state can be in a solidified state when the temperature of the portion 24 ′ decreases. As described above, the pores 10 that may exist in the solidified layer 24 can be reduced.

In addition, as shown in FIG. 5, the irradiation conditions of the light beam L may be adjusted to reduce the pores 10 in the solidified layer 24 that has already been formed.

In one embodiment, in the solidified layer forming stage, when the number of occurrence locations of the pores 10 specified using the above-described infrared camera exceeds a predetermined standard, for example, as shown in FIG. You may change the output of L suitably. Specifically, when the number of occurrence locations of the pores 10 exceeds a predetermined standard, it is determined that there is a large amount of residual gas that can cause the pores 10 in the solidified layer 24, and light is accordingly emitted. The output of the beam L may be increased. When the output of the light beam L is increased, a relatively large irradiation heat of the light beam L is provided to a predetermined portion of the already formed solidified layer 24 including the pores 10 located in the lower layer. Can be. Thereby, the predetermined part of the already formed solidified layer 24 including the pores 10 can be suitably brought into a molten state. Thereafter, as the temperature decreases, a predetermined portion of the already formed solidified layer 24 including the pores 10 in a suitable molten state can be suitably solidified. Thereby, the pores 10 already formed in the solidified layer 24 can be suitably reduced. For example, as shown in FIG. 5A, the light beam L is compared with that in the normal solidified layer formation, depending on the degree of occurrence of the identified pores 10 that exceeds the predetermined reference. It may be determined how much to increase the output of. As an example, when the number of occurrence locations of the specified pore 10 that exceeds the predetermined standard is relatively small, the degree of output of the light beam L that is increased as compared with the normal solidified layer formation. May be relatively small. When the number of occurrence locations of the specified pores 10 that exceed the predetermined standard is relatively large, the degree of output of the light beam L to be increased is relatively large as compared with the normal solidified layer formation. It's okay.

In one aspect, in the solidified layer forming stage, when the number of occurrence locations of the pores 10 specified using the above-described infrared camera exceeds a predetermined reference, for example, as shown in FIG. The scanning speed of L may be changed as appropriate. Specifically, when the number of occurrence locations of the pores 10 exceeds a predetermined standard, it is determined that there is a large amount of residual gas that can cause the pores 10 in the solidified layer 24, and light is accordingly emitted. The scanning speed of the beam L may be reduced. When the scanning speed of the light beam L is reduced, the irradiation heat of the light beam L is provided relatively sufficiently to a predetermined portion of the already formed solidified layer 24 including the pores 10 located in the lower layer. Can be. Thereby, the predetermined part of the already formed solidified layer 24 including the pores 10 can be suitably brought into a molten state. Thereafter, as the temperature decreases, a predetermined portion of the already formed solidified layer 24 including the pores 10 in a suitable molten state can be suitably solidified. Thereby, the pores 10 already formed in the solidified layer 24 can be suitably reduced. Note that, for example, as shown in FIG. 5B, the light beam L is compared with that at the time of normal solidified layer formation, depending on the degree of occurrence of the identified pores 10 that exceeds the predetermined reference. It may be determined how much the scanning speed is reduced. As an example, when the number of occurrence locations of the specified pores 10 that exceed the predetermined standard is relatively small, the scanning speed of the light beam L that is smaller than that at the time of normal solidified layer formation. The degree may be relatively small. When the degree of the number of occurrences of the specified pores 10 that exceed the predetermined standard is relatively large, the degree of scanning speed of the light beam L that is reduced compared to the normal solidified layer formation is relatively large. It can be big.

In one aspect, in the solidified layer forming stage, when the number of occurrence locations of the pores 10 specified using the above-described infrared camera exceeds a predetermined standard, for example, as shown in FIG. The spot diameter of L may be changed as appropriate. Specifically, when the number of occurrence locations of the pores 10 exceeds a predetermined standard, it is determined that there is a large amount of residual gas that can cause the pores 10 in the solidified layer 24, and light is accordingly emitted. The spot diameter of the beam L may be made smaller than that during normal solidified layer formation. When the spot diameter of the light beam L is reduced, a relatively large irradiation heat of the light beam L is provided to a predetermined portion of the already formed solidified layer 24 including the pores 10 located in the lower layer. Can be. Thereby, the predetermined part of the already formed solidified layer 24 including the pores 10 can be suitably brought into a molten state. Thereafter, as the temperature decreases, a predetermined portion of the already formed solidified layer 24 including the pores 10 in a suitable molten state can be suitably solidified. Thereby, the pores 10 already formed in the solidified layer 24 can be suitably reduced. For example, as shown in FIG. 5C, the light beam L is compared with that in the normal solidified layer formation, depending on the degree of occurrence of the identified pores 10 that exceeds the predetermined reference. It may be determined how much the spot diameter is to be reduced. As an example, when the number of occurrence locations of the specified pores 10 that exceed the predetermined standard is relatively small, the spot diameter of the light beam L that is smaller than that at the time of normal solidified layer formation. The degree may be relatively small. When the degree of the number of occurrences of the specified pores 10 that exceed the predetermined standard is relatively large, the degree of the spot diameter of the light beam L to be made smaller than that at the time of normal solidified layer formation is relatively large. It can be big.

In one embodiment, as shown in FIG. 6, a predetermined portion of the solidified layer 24 including the pores 10 may be pressed from the outside to reduce the pores 10 in the already formed solidified layer 24.

Specifically, as shown in FIG. 6, the location where the pores 10 are generated is specified, and the predetermined portion 24 ′ of the solidified layer 24 including the pores 10 is, for example, the cutting means 4 (however, a cutting blade is installed). May be pressed from the outside. The pressing direction may be a direction facing the stacking direction as shown in FIG. By pressing the predetermined portion 24 ′ of the solidified layer 24 including the pores 10 from the outside, the pores 10 can be crushed. Thereby, the pores 10 in the solidified layer 24 can be reduced. When the height of the uppermost surface 24a of the solidified layer before and after pressing the predetermined portion 24 ′ of the solidified layer 24 including the pores 10 is compared, the difference can be about 10 μm (see the enlarged view in FIG. 6). ). Therefore, it can be said that the flatness of the uppermost surface 24a of the solidified layer 24 is ensured.

Depending on the size and shape of the pores 10, the pores 10 may not be properly crushed only by pressing the predetermined portion 24 'of the solidified layer 24 including the pores 10 from the outside. Therefore, as shown in FIG. 7, the cutting means 4 is rotated by rotating the cutting means 4 while applying a pressing force to the predetermined portion 24 ′ of the solidified layer 24 including the pores 10 using the cutting means 4. A rotational force may be further applied to the predetermined portion 24 ′ of the solidified layer 24. Thereby, the pore 10 can be crushed more suitably. As a result, the pores 10 already formed in the solidified layer 24 can be more suitably reduced.

In one embodiment, as shown in FIG. 8, the predetermined portion 24 ′ of the solidified layer 24 including the pores 10 may be subjected to cutting to reduce the pores 10.

Specifically, after specifying the location where the pores 10 are generated using an infrared camera, a predetermined portion 24 ′ of the solidified layer 24 including the pores 10 as shown in FIG. 4 is used for cutting. When subjected to the cutting process, as shown in FIG. 8B, the predetermined portion 24 ′ of the solidified layer 24 including the pores 10 cannot exist in the solidified layer 24. After the predetermined portion 24 ′ of the solidified layer 24 including the pores 10 does not exist in the solidified layer 24, the powder 19 is applied to a place where the predetermined portion 24 ′ does not exist as shown in FIG. Fill. After filling the powder 19, as shown in FIG. 8D, the portion filled with the powder 19 is irradiated with the light beam L to melt and solidify the filled powder 19. As described above, the pores 10 can be reduced from the already formed solidified layer 24.

In one embodiment, as shown in FIG. 9, the supply conditions of the powder used for forming the solidified layer may be adjusted to reduce the pores in the already formed solidified layer.

In one aspect, when the number of occurrence locations of the pores 10 specified using the above-described infrared camera exceeds a predetermined reference, the following aspect may be taken. Specifically, it is determined that there is a large amount of residual gas that can cause the pores 10 in the solidified layer 24, and the squeezing blade 23 is formed accordingly, for example, as shown in FIG. The thickness of the powder layer 22 may be adjusted as appropriate. For example, as shown in FIG. 9A, the thickness of the layer is set to L ₁ , L ₂ (> L) according to the degree of the number of occurrence locations of the specified pore 10 that exceeds the predetermined standard. ₁ ), or L ₃ (> L ₂ ). When the thickness of the powder layer 22 becomes relatively small, when a new solidified layer is formed by irradiating a predetermined portion of the powder layer 22 with a light beam, the powder layer 22 already includes the pores 10 located in the lower layer. The irradiation heat of the light beam can be suitably provided to a predetermined portion in the formed solidified layer 24. Thereby, the predetermined part in the already formed solidified layer 24 including the pores 10 located in the lower layer can be suitably brought into a molten state. Thereafter, as the temperature decreases, a predetermined portion in the already formed solidified layer 24 including the pores 10 located in the lower layer in a suitable molten state can be suitably solidified. Thereby, the pores 10 already formed in the solidified layer 24 can be suitably reduced.

In addition, although it demonstrated based on the aspect which forms the solidified layer mainly by the powder bed fusion | bonding method (so-called powder bed system) until now, it is not limited to this, For example, as shown in FIG.8 (b), it is a powder spray. The solidified layer may be formed by a method. Here, the “powder spray method” is a method of forming a solidified layer by performing powder supply and light beam irradiation substantially simultaneously. In contrast to the powder bed fusion bonding method (so-called powder bed method), the powder spray method has a feature that no powder layer is formed when a solidified layer is obtained. That is, in the powder spray method, a light beam is irradiated to a powder supply location, and a solidified layer is formed from the supplied powder by supplying powder or the like directly to the powder supply location.

In one aspect, when the number of occurrence locations of the pores 10 specified using the above-described infrared camera exceeds a predetermined reference, the following aspect may be taken. Specifically, it is determined that there is a large amount of residual gas that can cause the pores 10 in the solidified layer 24, and the powder 19 is supplied from the powder supply nozzle 80 accordingly, for example, as shown in FIG. The thickness of the layer formed of the powder 19 may be adjusted as appropriate. For example, as shown in FIG. 9B, the thickness of the layer is set to L ₁ , L ₂ (> L) according to the degree of the number of occurrence locations of the specified pore 10 that exceeds the predetermined standard. ₁ ), or L ₃ (> L ₂ ). When the thickness of the layer made of the powder 19 is relatively small, when the newly supplied powder 19 is irradiated with a light beam to form a new solidified layer, the pores 10 located in the lower layer are included. The irradiation heat of the light beam can be suitably supplied to a predetermined portion in the already formed solidified layer 24. Thereby, the predetermined part in the already formed solidified layer 24 including the pores 10 located in the lower layer can be suitably brought into a molten state. Thereafter, as the temperature decreases, a predetermined portion in the already formed solidified layer 24 including the pores 10 located in the lower layer in a suitable molten state can be suitably solidified. Thereby, the pores 10 already formed in the solidified layer 24 can be suitably reduced.

In one aspect, when the number of occurrence locations of the pores 10 specified using the above-described infrared camera exceeds a predetermined reference, the following aspect may be taken. Specifically, it is determined that there is a large amount of residual gas that can cause the pores 10 in the solidified layer 24, and the powder 19 is sucked from the powder suction nozzle 90 accordingly, for example, as shown in FIG. The thickness of the layer formed of the powder 19 may be adjusted as appropriate. For example, as shown in FIG. 9C, the thickness of the layer is set to L ₁ , L ₂ (> L) according to the degree of the number of occurrence locations of the identified pore 10 that exceeds the predetermined standard. ₁ ), or L ₃ (> L ₂ ). In addition, when the thickness of the layer made of the powder 19 becomes relatively small, when the powder 19 is irradiated with a light beam to form a new solidified layer, the powder 19 is already formed including the pores 10 located in the lower layer. The irradiation heat of the light beam can be suitably provided to a predetermined portion in the solidified layer 24. Thereby, the predetermined part in the already formed solidified layer 24 including the pores 10 located in the lower layer can be suitably brought into a molten state. Thereafter, as the temperature decreases, a predetermined portion in the already formed solidified layer 24 including the pores 10 located in the lower layer in a suitable molten state can be suitably solidified. Thereby, the pores 10 already formed in the solidified layer 24 can be suitably reduced.

<Mode for reducing pores that may be generated in a newly formed solidified layer>
In the above, the embodiment for reducing the pores generated in the already formed solidified layer has been mainly described. However, in order to reduce the pores that can be generated in the newly formed solidified layer, the following embodiment may be adopted. .

Specifically, pores that may be generated in the newly formed solidified layer may be reduced according to the following embodiment.

As described above, when the irradiation heat of the light beam L is transmitted to the solidified layer 24A located in the already formed lower layer, the residual gas 5 that can locally remain in the solidified layer 24A is expanded by the irradiation heat of the light beam L. Then, the expansion of the residual gas 5 may locally generate pores 10 in the solidified layer 24A (see FIG. 2). Although not bound by any particular theory, it can be considered that such residual gas 5 is particularly likely to be generated as the temperature of the solidified layer at the time of formation increases. Therefore, in view of this point, when forming a new solidified layer, in order to suppress in advance the generation of the residual gas 5 that may cause the pores 10, the light beam L is compared with that during normal solidified layer formation. The irradiation conditions of the light beam L are adjusted such that the irradiation energy of the light beam L is relatively reduced, the scanning speed of the light beam L is relatively increased, and / or the spot diameter of the light beam L is relatively increased. Is good. Further, the present invention is not limited to this, and when a new solidified layer is formed, in order to suppress in advance the generation of the residual gas 5 that may cause the pores 10, a solidified layer (modeling that has already been formed as a base material) is formed. The temperature of the new powder layer by lowering the temperature of the object) and / or the modeling plate.

As mentioned above, although one Embodiment of this invention has been demonstrated, it has only illustrated the typical example of the application scope of this invention. Therefore, those skilled in the art will readily understand that the present invention is not limited thereto and various modifications can be made.

One embodiment of the present invention as described above includes the following preferred modes.
First aspect :
A method for producing a three-dimensional shaped object by sequentially forming a plurality of solidified layers by irradiation with a light beam,
A method for producing a three-dimensional shaped object comprising reducing pores generated due to residual gas in the solidified layer.
Second aspect :
In the first aspect described above, the method for producing a three-dimensional shaped article, wherein the pores generated in a high density region having a solidification density of 80 to 100% in the solidified layer is reduced.
Third aspect :
In the said 1st aspect or the 2nd aspect, the manufacturing method of the three-dimensional shape molded article which pinpoints the generation | occurrence | production location of this pore based on the temperature difference of the said pore and the peripheral part of this pore.
Fourth aspect :
In the third aspect, a method for producing a three-dimensional shaped article, wherein a predetermined portion of the solidified layer including the pores is irradiated with the light beam to melt and solidify the portion to reduce the pores.
Fifth aspect :
In the said 3rd aspect or the 4th aspect, the said predetermined part of the said solidification layer containing the said pore is pressed from the outside, The manufacturing method of the three-dimensional shaped molded article which reduces the said pore.
Sixth aspect :
The method for producing a three-dimensional shaped structure according to any one of the third to fifth aspects, wherein the predetermined portion of the solidified layer including the pores is subjected to a cutting process to reduce the pores.
Seventh aspect :
In any one of the first to sixth aspects, the solidified layer is formed by a powder bed melt bonding method.

Various articles can be manufactured by carrying out the manufacturing method of a three-dimensional shaped object according to an embodiment of the present invention. For example, in “when the powder layer is an inorganic metal powder layer and the solidified layer is a sintered layer”, the resulting three-dimensional shaped article is a plastic injection mold, a press mold, a die-cast mold, It can be used as a mold such as a casting mold or a forging mold. On the other hand, in “when the powder layer is an organic resin powder layer and the solidified layer is a hardened layer”, the obtained three-dimensional shaped article can be used as a resin molded product.

Cross-reference of related applications

This application claims priority under the Paris Convention based on Japanese Patent Application No. 2016-130009 (filing date: June 30, 2016, title of invention: “Method for producing three-dimensional shaped object”) . All the contents disclosed in the application are incorporated herein by this reference.

5 Residual gas 10 Pore 19 Powder 24 Solidified layer 24 ′ Predetermined portion of solidified layer 60 Temperature range of pore generating portion 70 Temperature range of peripheral portion of pore generating portion 100 Three-dimensional shaped object L Light beam

Claims

A method for producing a three-dimensional shaped object by sequentially forming a plurality of solidified layers by irradiation with a light beam,
A method for producing a three-dimensional shaped object comprising reducing pores generated due to residual gas in the solidified layer.
The method for producing a three-dimensional shaped article according to claim 1, wherein the pores generated in a high density region having a solidification density of 80 to 100% in the solidified layer is reduced.
The method for producing a three-dimensional shaped article according to claim 1, wherein a location where the pores are generated is specified based on a temperature difference between the pores and a peripheral portion of the pores.
The method for producing a three-dimensional shaped article according to claim 3, wherein a predetermined portion of the solidified layer including the pores is irradiated with the light beam to melt and solidify the portion to reduce the pores.
The method for producing a three-dimensional shaped object according to claim 3, wherein the predetermined portion of the solidified layer including the pores is pressed from outside to reduce the pores.
The method for producing a three-dimensional shaped object according to claim 3, wherein the predetermined portion of the solidified layer including the pores is subjected to a cutting process to reduce the pores.
The manufacturing method of the three-dimensional shape molded article according to claim 1, wherein the solidified layer is formed by a powder bed fusion bonding method.